Ableton Forum

Create a folder outside your Ableton map (like C:\My ableton projects).
Click it in the ableton browser: you now can create a project there; the option won't be longer greyed out

Sub 7:

I'm using RAM Idle LE (it is free; google it). It is showing your free RAM in the right corner of the Windows XP tray area. Very handy. For instance: if you're loading a VST into Ableton, or any other DAW, you can directly see, how much RAM it is using, etc

Try to disable hyperthreading in your BIOS (when starting up your PC)

I also was getting very serious stutters using my (fabulous) Pianoteq 2 as a VST.
Then an Angel came and spoke to me: UNcheck "multicore rendering" in the options menu of Pianoteq. And that did the trick for me !
But will it help you ?