http://www.emachines.com/support/product_support.html?cat=Desktops&subcat=T%20Series&model=T5048here you will find all drivers for your emachine ...
so ..assuming that you do not have expiriance ...I will try to explain in short how to do it ...
just insert the cd ...( be sure ya have the cd key if needed..) ...restart and press del to enter bios for to change the boot order to boot first from cd ...or ...
you can press F8 at start and choose to boot from cd and enter ...it will boot one time from cd ..and enter windows set-up..
after inspecting your computer will load primary drivers ..and ask you for the agreement press F8 again to agree...
inm this moment it will scan for previous installations and will show findings ...this is the moment that you press esc for to not repair or any ...than choose the C partition ...and see that you have D for delete it ...than enter to continue and L to confirm ...than C to create again and enter to format ....CHOOSE TO FORMAT INTO ntfs MODE...QUICK OR NORMAL ...
If you didnt format it a lot it doesnt matter too much ..but normal NTFS will take longer to do it , but it has a better efect ...from now on it will load the files ..and restart to continue the installation ..
the other partitions just format them from the windows ...by right click them ...and choose format ..from the list of commands..