Taskbar at bottom of games, performance poor

[networkn]

Hi There!

I have noticed that frequently I get the start bar showing at the bottom of my gaming window. It happens a fair bit and sometimes alt tabbing twice gets rid of it (and sometimes crashes my games). I have a HD5970 but it was happening with my 4870x2 as well.

When games are like that, the performance drops horrendously.

Two questions;

1) Can I stop it occurring?
2) how can I stop my games crashing during alt tab. Dirt2 and Just Cause 2 it occurs a lot (Not every time).

Thanks in Advance.

[Abram]

Only thing i can think of is updating your drivers and changing your taskbars' Auto-Hide option.

Detailed specs would be helpful, too.