Having 3.5 gigs of free space may not be enough. Default for your recycle bin is 10% of your drive, and I cant recall the amount of disk space system restore needs but its quite a bit also, then windows needs even more free space just for moving files around while you use windows.
This tweak guide can explain, and help you try to free up more disk space, if in fact this is what your problem is.
See the cleaning windows section...
My desktop configuration is as follows:
CPU: AMD Athlong 64 2800+
OS: Windows XP Home Edition version 2002, service pack 3
RAM: 1 GB
HDD: 2 x 40 GB (primary-secondary, not RAID)
Logical Partitions: 3 on primary drive - C is 10 GB, D is 15 GB, E is 15 GB. 1 on secondary drive (G).
The problem I am facing is as follows:
Boot partition (C) has about 3.5 GB free. As I start using the PC, the free space on C partition keeps reducing. It does not matter what I am doing - accessing internet, playing games or working with Open Office. Finally, after some time the free space falls below 200 MB and I start getting Low Disk Space warning.
I have cleaned up old files from this partition. The pagefiles are on D drive and secondary drive (G). The frequency of creating SR points by Windows is reduced to once a month.
I run Zone Alarm Internet Security (Firewall + Anti-virus + Anti-spyware). It is up-to-date and it has not found any virus or spyware.
I also run Iolo System Mechanic and it has not reported any problems.
I read in some earlier discussions that temp files created by AV programs or SR points created by similar tools can cause this issue. Has such issue been reported with Zone Alarm or System Mechanic?
I created a BAT file to report directory and file sizes for "C:\Windows", "C:\Program Files" and "C:\Documents and Settings" at regular intervals. There is some increase in size of some files in C:\Windows\Internet Logs and C:\Windows\Logs but that does not match the corresponding decrease in available free space (the decrease is greater).
Please let me know what the probable causes can be and what can I do to fix this.