Hey Techy_pal, thanks for responding. I'm already on the A10 BIOS (got the machine on Wednesday this week, so it's pretty new) and one of the first things I did upon getting the system was to install the latest GeForce 8400M GS driver. The driver is here:

http://support.dell.com/support/downloads/download.aspx?c=us&l=en&s=gen&releaseid=R180763&SystemID=XPS_M1330&servicetag=6M7QQ3J&os=WLH&osl=en&deviceid=13678&devlib=0&typecnt=0&vercnt=3&catid=-1&impid=-1&formatcnt=1&libid=6&fileid=246509

and dated 18th March 2008, but when installed the driver properties page shows a date of 22nd Feb 2008. Does anyone have any other suggestions?

Try to update the BIOS http://ftp.us.dell.com/bios/M1330A10.EXE   and you can even update the video drivers. Everything should be fine after this. 

Uninstall the video card driver ( Device manager, right click on your video card, uninstall ) Vista will probably load some generic driver it has for it.... Reinstall  the original driver that came with the laptop ( should be on your driver disk ) .. now force the laptop to sleep and wake it up to see if the problem persisits.. do this a couple of times to be sure...

now.. uninstall the driver again and install your updated driver ( driver dates are always off from when the release dates say ) and try the force sleep/wake up again...

This way you will be able to tell if its a driver issue or not..

Powermizer may or may not play a role in also.. while trying the above tests, try it with both powermizer on and off...

anyways....hope some of this helps.. let us know how it goes :)

Hello  Frinend,

Take this resoltion which works for me most of the times,

CLick on start, type task schudular, when you see task schedular(RIght click on the same & select run as administrator), Click Continue for the UAC prompt.
In the left pane, expand Task Scheduler, Task Scheduler Library, Microsoft, Windows, and click on MobilePC.

In the middle pane, right click on TMM.  Click on Disable.

CLose the task ashedular, Restart the system & Then try to place the system is sleep mode.

IT works like magic!!!!!!!!!!!!!!!!!!!

Let me know the results!!!!!!!!!!!!

Regards

Sam

Please see my original thread:

http://www.dellcommunity.com/supportforums/board/message?board.id=vista&thread.id=21571

This problem seemed to go away for me on, my xps m1710, with the A07 Bios and newer NVidia drivers. However, I have just bought a new m1330 and the problem is now happening all over again. My m1330 has a completely clean install of Vista SP1 with all the latest drivers and the A10 bios (the machine was built by Dell within the past week).

It seems to me likely that Dell fixed the problem in the m1710 bios A07, only to not include the fix in the m1330 bios series.  I hope I'm wrong ....

NigelS