No sound after reinstalled windows xp pro

for which Operating System? 98se and millenium edition are obsolete. win xp pro and above are still good.
what device are you having problems with? usb? sound card? video card? or other device? or is it just missing some DLL files from the operating system?
there is also another issue with win xp pro and srv pak 3 it forces the only "signed drivers only" to be installed!! therefore if you have srv pack 3 installed then you will need to to the computer to install any ways. windows 7 will not install "un-signed device drivers" this makes most your devices incompatible with win 7!!
there is another with windows systems up-grades that do not include any kind of driver support except for basic motherboard devices and limited sound cards and video cards and usb port support.
you may want to check your computer maker for any device drivers for the last 3 years only and if it was a device that came with your computer.

You need to reinstall it again, the boot manager (the file that launches Windows) is missing .

reinstall windows xp pro. in different folder
and keep all the files

If you have a valid Win XP Pro CD and want to install the operating system you'll need to format your hard disk drive. If you have allot of data on you're hard disk drive, (In Win 2000) Suggest you create a second partition within the free space of you're hdd and install windows XP Pro. Boot you're system with the XP CD. Pay close attention to the display screens. Follow the instructions for creating a second partition.
Format the new partition. (Quick). Install windows XP on the new partition. Once completed you can copy your personal data to win XP.
If you choose to keep the win 2000 partition and you do not wish to have a dual boot system than remove/delete the root files from the 2000 partition. These files; Autoexec.bat and Boot.ini. You're new XP Boot.ini should read like this;
[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect /usepmtimer
Once you're satisfied an no longer need win 2000 use windows diskmgmt.msc from the run command to delete the win 2000 partition.
Win 2000 uses a FAT16 where Win XP uses the FAT NTFS.

Cheers!
Mike

I would suggest re-reinstalling the drivers

Run a Chkdsk:
Take the Windows XP disk. Boot from it, then DO NOT select F2 (automated system recovery) but continue through the procedure until you get to the point where you can choose between installing Windows XP and entering the Recovery Console. Once you get into the Recovery Console, do chkdsk and fix potential errors on your disks! Chkdsk C: /R


OR:


Perform an XP repair:
When you boot with the Win XP install CD-ROM, it loads a minimal operating system, similar to DOS, but compatible with Win XP. At the first screen you select install Win XP (not Recovery Console) and at the next screen it will find that you already have Win XP and offer to attempt a repair. This repair should not touch your Applications or data; it just reinstalls the Windows files. This is great because when it works you don't need to reinstall all your software.

If I could be of further assistance, let me know. If this helps or solves the issue, please rate it.
Thanks, Joe


I’m happy to assist further over the phone at https://www.6ya.com/expert/joe_8b8c2cd6ce148309

Did you replace the fan?

Is it XP:
If so do a repair on XP:

XP repair
When you boot with the Win XP install CD-ROM, it loads a minimal operating system, similar to DOS, but compatible with Win XP. At the first screen you select install Win XP (not Recovery Console) and at the next screen it will find that you already have Win XP and offer to attempt a repair. This repair should not touch your Applications or data; it just reinstalls the Windows files. This is great because when it works you don't need to reinstall all your software.
If I could be of further assistance, let me know. If this helps or solves the issue, please rate it.
Thanks, Joe


I’m happy to assist further over the phone at https://www.6ya.com/expert/joe_8b8c2cd6ce148309

http://www.nvidia.com/object/nforce_audio_4.62_win2kxp.html

copy and paste this file in to your address bar abileve this is a generic xp audio driver

The best thing to do is borrow a Win XP cd from a friend and do the following:
When you boot with the Win XP install CD-ROM, it loads a minimal operating system, similar to DOS, but compatible with Win XP. At the first screen you select install Win XP (not Recovery Console) and at the next screen it will find that you already have Win XP and offer to attempt a repair. This repair should not touch your applications, it just re installs the Windows files. This is great because when it works and you don't need to reinstall all your software.

If I could be of further assistance, let me know. If this helps or solves the issue, please rate it.
Thanks, Joe


I’m happy to assist further over the phone at https://www.6ya.com/expert/joe_8b8c2cd6ce148309

Why would you torture yourself with that old thing?  Yeah, you can create more boot script lines...they should designate the proper root for the second volume and that ought to fix any missing file issues if indeed ICG32.dll and company are where they started....