Had a really bad virus which started off as a fake windows security?

I don't know what the f*ck went wrong I have malware bits and Micro Security essentials, I must of got infected with a fake windows security adware as i carelessly download stuff without scanning ( I understand that this was silly) I tried clearing all these infected through my MSE and it took me 13 hours for a full scan with around 80 infected files, I press delete all and there goes all my ******* software startups haha, My photoshop, Adobe flash, Winrar, RocketDock, Filezilla, Firefox, IE, Google chrome, Adobe reader, Full microsoft office suite, basically everything but the ******* virus. I purchased my computer with windows xp installed, I was wondering is there anyway i can clear the virus or get Windows xp download as i have the key but not the disk, today i decided to scan it again with avast! I SCANNED 1% OF MY 2 MILLION FILES AND FOUND THAT I HAD 73,612 Infected out of 200, 000 scanned, So am ****** lol any tips and no like telling me to del win32