Games are memory intensive and this old OS has an issue with those 64 thousand byte fixed size resource pools. NO FIX will be forthcoming and rebooting is the easy out.
In closing, I would not fix this if this is your only issue since fixing can bring up new issues to fix.
Bob
Sometimes, almost always after I have played a game, when I return to the destop the Icons are no longer clickable. If I left click an Icon, I just get information on the properties. Sometimes it lasts only a short time, sometimes until I reboot.
If I right-click, I can select OPEN. Why does this happen?
Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic