[sassan]

Not sure but could very well be due to your low real or virtual memory.

Try to increase your RAM if you can. Even if this issue is not taken care off, you still will see a lot of improvement on PS function that is a really memory hungry software.

Make sure your hard drive has adequate free space (At least 10 GB or so) that is where your temporary files get collected and it is so easy to fill it up with PS.
Cleaning your Temp (Temporary files) also help a lot. If you are a window user, click on Start, then Run and type exactly:
%temp%
When the list appears (All junks taking your hard drive space in Temp folder) select all and delete all. Warning! Well if something very bad happened to you, Of course I take no responsibility what so ever and don't run after me for liability... So do everything at your own risk.

Reduce the number of History for your picture post processing work, under the setting in PS.

Try to save less on PS format as it really takes up huge amount of HD space, that is unless if you save your files on an external drive or likewise that doesn't cause any shrinkage of your valuable, badly needed primary Hard drive.

Report back if none worked to see what else can be done.

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Christine: Wasn't that the activated "Cap lock" that kept you in that special mode?
Turn the Cap lock off and hopefully you have your curser back.