A friend has the following:

Intel Pentium III, 800 mhz, 512 ram
Windows XP
10 gb hard drive

Her COMPUTER has started reporting shrinking hard drive space over the last 2 weeks...she had 4 gb free a month ago...three days ago had only 200mb free and now has only 98MB free...something is very very wrong here.

Any suggestions for me to forward to her?
My thoughts are: SPYWARE, virus, etc....

Has Norton, but no anti spyware...Norton is out of date and not updated for almost a year...I've already scolded her about that snafu...inexcusable IMHO...anyone ever had this particular problem occur?  As always, thanks much in advance...this FORUM is the best!  Because of you folks, I've kept my system running flawlessly:)))
First delete something off that hard drive so it will continue to run. 15% free is a safe minimum.

Start by running Disk Cleanup, and empty the recycle bin.

There are several free things to download (just google for them):

AdAware
Spybot
AVG Free
CCleaner
Ewido

Make sure they are up to date, then run the programs in safe mode.

Do this and we will go from there. After there is space, download all of the Windows updates and SP2, if not done yet.

Is there a Windows CD present if things need to be reloaded (just in case)?
Update all of these and then run in safe modeI was thinking along those lines as well...yes, there is a Windows XP OS disk in case a REINSTALL becomes necessary.  I've run XP on my old Pent.II machine and have been able to keep it free of problems, though it is slow at times...have never had the problems this other computer is reporting though.  Will follow those steps and then let you know where things stand.  Thank you for the prompt reply GX1_Man!!! And suggest to her to get another HDD for some storage space...an 80G is only 30 bucks or so.And while your at it, make Indexing service is disabled.Nice catch 2K...Hm, it might possibly be a backdoor trojan, etc. Try downloading the trial version of 'The Cleaner', and run that. It scans hidden files, too, so it's pretty nifty. Alerted me to many-a-threat!

( I had this same problem a while back, It's very important to keep firewalled, antivirused etc these days. )