What are you using to see the amount of memory in use, like 35% then
eventually 90%?

I agree with the guy who said go into Task Mgr / Processes and see
which tasks are using the memory.

Another couple ideas to narrow it down, if you think you know what the
culprit is, to test the theory:

- Go into MSCONFIG and under the Services & Startup tabs, disable all
non-essential non-MS startups and services, then see if PC can idle
for a few days without gobbling up all mem.

- Along the same lines, try booting into Safe Mode and see if it can
idle a few days without gobbling up the mem.

Or if you don't know what the culprit is perhaps you can use those
techniques to determine by process of elimination.

Perhaps some program or even OS component has a debug trace or log
turned on which is stored in mem and the longer you run the more it
consumes.