I came across this while researching the same issue. I thought I should mention that I found a solution that doesn't require reinstalling Parallels Tools or if reinstalling doesn't work.
I realized I started getting this problem after rebooting my Fedora VM the first time after updating the kernel (actually several weeks later). The problem appears to be an incompatibility between updated Linux and the version of Parallel tools installed. Unfortunately, reinstalling Tools doesn't always work for some new kernel versions. I got a compile error in the parallels update log when trying to update.
What you need to do is fallback to booting into the previous version of the kernel. This isn't as easy with Fedora 15 as with earlier versions, but during the boot process, press the Return key before blue bar appears. This brings up the Grub menu, and you can select the kernel version that worked.
Now, you want to boot into the older kernel by default, so when booting is complete edit the file /boot/grub/grub.conf file (using sudo or as root) and swap the lines associated with the earlier version of the kernel with the ones on top. For instance, if your grub.conf is:
Code:
default=0
timeout=0
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Fedora (2.6.40.4-5.fc15.i686)
root (hd0,0)
kernel /vmlinuz-2.6.40.4-5.fc15.i686 ro root=/dev/mapper/vg_fedora-lv_root rd_LVM_LV=vg_fedora/lv_root rd_LVM_LV=vg_fedora/lv_swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us rhgb quiet
initrd /initramfs-2.6.40.4-5.fc15.i686.img
title Fedora (2.6.38.6-26.rc1.fc15.i686)
root (hd0,0)
kernel /vmlinuz-2.6.38.6-26.rc1.fc15.i686 ro root=/dev/mapper/vg_fedora-lv_root rd_LVM_LV=vg_fedora/lv_root rd_LVM_LV=vg_fedora/lv_swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us rhgb quiet
initrd /initramfs-2.6.38.6-26.rc1.fc15.i686.img
Change this to:
Code:
default=0
timeout=0
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Fedora (2.6.38.6-26.rc1.fc15.i686)
root (hd0,0)
kernel /vmlinuz-2.6.38.6-26.rc1.fc15.i686 ro root=/dev/mapper/vg_fedora-lv_root rd_LVM_LV=vg_fedora/lv_root rd_LVM_LV=vg_fedora/lv_swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us rhgb quiet
initrd /initramfs-2.6.38.6-26.rc1.fc15.i686.img
title Fedora (2.6.40.4-5.fc15.i686)
root (hd0,0)
kernel /vmlinuz-2.6.40.4-5.fc15.i686 ro root=/dev/mapper/vg_fedora-lv_root rd_LVM_LV=vg_fedora/lv_root rd_LVM_LV=vg_fedora/lv_swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us rhgb quiet
initrd /initramfs-2.6.40.4-5.fc15.i686.img
When or if Parallels releases a new version of the Tools to support the newer kernel, you can swap the grub.conf lines back so you boot into the new kernel.
By the way, to show the grub menu on every boot, remove the line hiddenmenu and set the timeout to eg 5 (wait 5 seconds before booting)