After upgrade to 5 dosn't start VM created with 4

Hello,
My configuration is the following:
* MacPro build 10C540 with 2 x 2.8Ghz QuadCore Xeon, 8Gb DDR2 and an internal RAID5 array
* MacOS 10.6.2 with all the updates
* Always used Parallels 4 with a Windows XP Professional license w/SP3 as guest OS: 'till yesterday it worked like a charm
* VM had 2 processors dedicated, and 3.096 Gb of RAM

This morning I've installed the Parallels 5 upgrade (v. 5.0.9220 rev. 531144)
When double clicked th VM starts booting the OS, than when it arrives at the black screen with the Windows logo and the animated bar, it displays a BSoD:
WORKER_THREAD_RETURNED_AT_BAD_IRQL
[...]
STOP: 0x000000E1 (0x8057EA01, 0x00000000, 0x80568CC0)
And restarts.

I've installed (on Parallels 5) a new VM using Windows 7 Ultimate 64 bit, and it seems to work like a charm. So it's a problem due to the Windows XP VM created with the version 4.

I NEED to open it, at least to retrieve the files, and copy them in the VM with Windows 7.

Thanks for any hint.

 

try follow workaround:

1. assign to VM 1 CPU
2. load guest OS
3. install new Parallels tools
4. shutdown guest OS
5. assign to VM 2 CPU again

 

Thank You Sandro: it worked! ^_^
Thanks a lot: silly of Me I didn't try the same work-around advised in this [sticky] thread.
Shame on My laziness… /