Tune-up Utilities 2007 is my choice of diagnostics Richard, it works for me, although you can try something aggressive like Norton's Disk Doctor, but you'll have to purchase them.

Sounds like you've lost some sectors within some clusters and you want your space recovered.

Did you check your sectors, file allocation and boot sector integrity with scandisk? If you did, do you have lost sectors? That would be the first thing to check. Make sure you have everything running in the background on your system closed before scanning.

I also suggest you not to check “automatically fix file system errors” and “scan and attempt recovery of bad sectors” on the first pass. You want to see if you can get a clean scan on the first pass and checking these aggressive features will cause your initial verification to be lengthy.

Your last resort is to unconditionally format the drive providing you can't recover the space with utilities, meaning back-up everything you want to and can keep.

Drives go bad, quickly, unexpectedly and always painfully. They can come from the manufacturer with up to 9 bad clusters and is deemed acceptable for sale.

Guys like us have to always prepare for disaster.

Good luck my friend.

Cp

try this to see where the files are...
WWW Link

I forgot to add that you should be concerned, that's a lot of lost space.

Let us know how it goes.

Rich, Like CP I use TuneUp 2007 Utilities. If your defrag does not give you the answer try the free 30 day trials of TuneUp and PerfectDisk - they are both the full versions of the product - and between them they should sort you out.   

how old is it?
did you buy it new or eBay?
do you have more then one partition?

Gremlins

Richard right click on your c drive and choose properties. Click on Disk Cleanup and check all the boxes. When I got my computer I had about 25gb of junk on it.

or

If you went from XP to Vista there is a folder called Old files(?) when you click on the c drive. That holds about 90gb.

Yeah, forgot to mention that it's free...lol

also check your pagefile, if your page file is managed by windows, then it is possible high activity would cause it to grow in size. Loosing 100GB is to much to use up with general usage.

Suggestion...
1.) clean all temp files and recycle bin, basically run a clean disk utility.

2.) uninstall any software that is unknown and uneeded (make sure the software you uninstall is not system necessary)

3.) defrag the drive with a good defragger, windows defragger sucks, my suggestion is O&O Defrag Professional or Perfect Disk or Diskeeper. all of these are faster than the Windows defragger and they do a better job. (also auto defrag and other features)

Some harddrive clean ulities have a free space cleaner as well. It overwirites the unused portion of the harddrive to make sure that the files not logged on the MBR are indeed empty.

If all else fails you may want to try repairing the MBR (Master Boot Record), it could be reading an error which may cause your space to be lost. If nothing else worksas a last and final resort is to back up your important data and reinstall windows. This is a gaurantee fix for these issues assuming that that problem isnt hardware related.

Keep us informed... plenty of people here to help.

No it's from dell...Have had good luck with them in the past so I stuck with them..It's says 179gb now...

Vista ..Don't use any video programs other than windows media player.I'll check it out, thanks...

Vista takes up a huge amount of space. I did the upgrade version of Vista Home Basic on my fathers computer and with just bare minimun of XP Home and then the upgrade of Vista Home basic, it took every bit of the 40Gb harddrive he has. I ended up getting the Vista off his computer. Vista is huge. But 100GB for system restore? I think is uses about 10% maybe 20 but thats pushing it.

But then again it all adds up... It won't take long for a few programs we think as minor to add up to a large amount of space

Now it's down to 178gb's. I haven't done anything...