Installer BLOAT

I was cleaning up a computer from another one of my company's stores, and couldn't figure out why the 80G drive only has less than 12G left. I went through and removed extraneous programs our company doesn't need on the computer, old personal files, as many things as possible. Ran AVG and spybot and neither found any problems. I was now up to approx. 15G free space. This still didn't seem right. I installed Spacesniffer to see what was hogging the drive. According to SS the installer area is taking up 51.7G drive space. Most of the files are .msp files ranging from 92K - 110.6M in size. I can't seem to find a way to dump these files. Any suggestions other than destructive format and reloading OS and Programs?

 

I forgot to mention the computer has XPSP3 on it.

 

This may do some of the lifting, have used on a few occasions :
http://support.microsoft.com/kb/290301

 

if you have ccleaner installed when using the cleaner in the windows tab under advanced check hot fix installers .if you don,t have ccleaner you can get it from here " http://www.majorgeeks.com/CCleaner_Slim_No_Yahoo_Toolbar_English_d4191.html ".
hope this helps.