virtualbox.org

I've been running XP in virtualbox for several years with no problem, on my Windows 7 Home Premium (Service Pack 1) 64 bit laptop.
Currently VBox is 4.2.12 r84980

After I tried updating to newer version (4.3.4) XP wouldnt boot so I reinstated the previous. That worked ok except I constantly had to "reboot using last successful ...." until today when all it shows after the VirtualBox splash screen is a black screen.
I believe this is all to do with VT-x, however I don't know how to fix it. I have essential data I must access somehow. I'm concerned that if I try to reinstall XP I may lose my data.
Can someone help me get past the black screen of death at least into safe mode?
(I have IO APIC enabled,
PAE/NX enabled)

VM log file please. Minimum information needed for assistance.

Incidentally, it isn't useful to tell us that IO APIC is enabled. What matters is whether the IO APIC setting is correct, i.e. matching what XP was installed with. Either enabled or disabled could be correct. Hanging on a black screen at boot time usually implies incorrect.

Sorry
Attached.

I've tried booting with IO APIC enabled and disabled. Same result.

VBox.log wrote: 00:00:03.105005 Host RAM: 3037MB total, 767MB available
...
00:00:03.968532 RamSize <integer> = 0x000000002e400000 (775 946 240, 740 MB)
00:00:03.969053 VRamSize <integer> = 0x0000000008000000 (134 217 728, 128 MB)

Your problem has nothing to do with VT-x, in fact your Celeron CPU doesn't support VT-x. Happily that isn't a problem since VT-x isn't needed to run XP-32bit in a single CPU mode. Your real problem seems to be that you simply don't have enough free memory to run this VM. You should attempt to free up as much host RAM as possible. I would also reduce the guests RAM allocation to 512MB and graphics RAM to 32MB.

Mpack, thanks for your help with this. Much appreciated.

I've adjusted the memory settings as you suggest, and run again with as much base memory as I can muster. This has always run ok on the laptop before so it should be able to cope. No difference though.

I've attached log again with new settings.

PathwayUK wrote:This has always run ok on the laptop before so it should be able to cope.

Well, the log is quite clear about how RAM is available on your host.

Unfortunately, there's no sign of what the problem could be. If I was you I would first make a backup of the VM so things can't get any worse, then I'd see if it will boot up in safe mode. Ultimately you should be able to read data off the drive by creating another VM and attaching this disk to it as a secondary drive. Hopefully you haven't used any snapshots.

Oh - and I would try disabling IO-APIC. The default XP template has this off by default, so if you created this VM using VirtualBox I find it unlikely that IO-APIC would be enabled.

Finally, I would dismount that VBox Guest Additions CD that's currently mounted.