Description of problem:
The installer freezed up (10 minutes) looking for existing fedora
installations when the MBR is stuffed.

Version-Release number of selected component (if applicable):
FC2 Test 3

How reproducible:
Every time

Steps to Reproduce:
1. Boot into single user mode, all disks read only
2. dd if=diskboot.img of=/dev/hda
3. Reset machine
4. Start installation
  
Actual results:
Installation freezes when searching for existing installations.  If
you kill -9 the lvm process which is searching, installation continues.

Expected results:
It should detect that something is dodgey, and continue.

Additional info:
The reason I'm installing like this, is cause I have a lab of old
Pentiums which i use as X-Terminals.  They don't have CDROMS, and the
BIOS won't boot of USB key.  Apart from the search for existing
partitions, the install works perfectly.