Solved: What's filling my C drive ?

HI,
Windows 7 desktop.
My C drive is filing up and I cannot seem to figure out what it is, maybe someone can tell what to look for.
For the last week or more, I noticed that my C drive is using up space at a fast rate, about 20 gbytes in the last week.
I have not run any large updates other that the windows update, adobe reader and whatever Secunia PSI updates .
I do not download movies, music or play games.
I ran malwarebyes, superantispyware and MSE, spywareblaster scans but there is nothing detected.
I ran ccleaner, disc cleaner, easycleaner.
I have cleared all deleted emails and checked any programs that need uninstalling.
I noticed that the C drive is down another 4gb since yesterday.
I used the PC mainly for emails, news and some banking. I do not click on to unknown sites nor pop-ups.
I ran Glasswire for a while to see if anything unusual is happening but all looks normal.
Any help would be appreciated.
Terryl.

 

Hi Phantom010

I have installed Treesize. I am working my way thru it. I cannot see anything other than windows using the disc space.
I managed to clear about 1.7 gb of space on clean up system files.
Thanks for your help.

 

Hi Phantom010
Treesize is very helpful and still monitoring it. The C drive space is still decreasing by about 1 GB a day.
I ran Glasswire and have noticed that my DNS server settings is changing daily, Realtek PCIe GBE family controller was changed. Could this be a problem ?
I am not on Wifi, connected by ethernet cable.
Thanks

 

No, I do not have uTorrent or any other file sharing app.
Thanks for the sevenforums.com site. Sifting through it. The problem is not freeing space, it is something that is using up space.Will keep you informed and hope to close this soon.
Regards

 

HI Noyb

My system restore was set to 50% and I have reduced it to 25% and I gained 20gb.
However, the problem was that the C drive was using about 1 gb every few days without my doing any downloads.
Thanks for your help.
Regards

 

I have checked my restore points and noticed that Microsoft created 12 restore points this month
My C drive was reduced by 2 gb since yesterday and had a restore point created this morning.
Could that have been the problem ? If so will put a solve on this.
Thanks again guys.

 

I have monitored this problem and it is related to the MSE creating a restore file before updating.
I used to have Avast but the last update created problems on my PC, so switched to MSE.
Thanks for all your help and will mark this as solved.
Regards