DEP prevents me from opening Control Panel

Is this normal - and if not how do I get around it? If I try to open Control Panel the first 2 or 3 times it closes some programs listed in the System Tray - then it finally allows me to open Control Panel but I get the "Windows Error" dialog box and it wants to shut down Explorer. If I ignore this I can finally get to the programs in Control Panel but eventually I have to close the dilog box and it shuts down Explorer. I have tried the OptIn and OptOut commands but they don't seem to have any impact. What am I doing wrong? Thanks. -bob

 

How do you know its DEP ?

 

I have on occassion, but not every time, gotten a message that DEP is the reason Explorer wants to close. The last time I tried I got this:

Error signature
AppNAme: explorer.exe AppVer:6.0.2900.2100 ModName: unknown
ModVer: 0.0.0.0 Offset: 02b044b0