Photoshop 7 weird behaviour when holding mouse button

I have Photoshop 7 on my laptop with Windows 8. Every time I holding left mouse button when setting something (for example slider of hue and saturation, etc.), after like 5 seconds Photoshop blinks and this setting window disappear, so I must click the Photoshop window and it appears again.

Another thing happening is when I use selection tool(L) and I am not clicking anywhere for 5 seconds, screen blinks and selection is automatically closed. This is anoying especialy when I use magnetic selection tool(L) when there is not necessary to click anywhere for longer time.