Lappy screen goes black for 20 seconds on bootup

[INS-ANI]

When ever i bootup,or log in to my desktop , my screen goes black for about 20 seconds and then it reappears.Is it normal. WIth vista basic it does happen, but all i have seen is the screen blinks for 3-5 seconds.
I use inspiron 1420 with ultrasharp truelife screen.

[sat123]

"my screen goes black for about 20 seconds and then it reappears" when it reappears what do u see the vista boot logo starts..or directly to windows login...

[INS-ANI]

The screen goes black after i log in, before and after the screen malfunction i see desktop.

[Sourabh]

I have Inspiron 640m (similar to the 1420 model) with Ultrabright screen. Sometimes, there is a blackout for a few seconds at startup but definitely not for 20 second. I'm presuming you don't have nVidia GeForce 8400M GS discrete GPU on the Inspiron 1420. Try removing Intel's igfxtray and igfxpers utilities from startup. If you don't have the latest drivers, you can even uninstall the existing drivers and reinstall with new ones.