Thanks for replies, but i've messed up. I used Partition Manager to resize the partitions to shrink them (to reduce the free space from like 50% to 10%) and now my pc won't boot, it just goes to a black screen with flashing cursor. It's straight after the first BIOS screen so can't get into Safe Mode or anything. Any ideas?
(Posted from my mobile)
Edit: Just run Windows 7 dvd Startup Repair, 1 problem detected, after restart still the same.
Edit2: It won't run a CHKDSK for Win7 G: (disk 1) "cannot open volume for direct access".
Edit3: the Win7 dvd is now recognising G: and the startup repair now says no problems detected, but still the same. Tried using DISKPART in Command Prompt to set G: as active (suggested by google result) but its unable to because its a Logical partition. Tried resetting BIOS to default too. I'll try 'extending' the partition using DISKPART in a sec...
Edit4: Extended it, but still the same.
<-- Bad choice, says JK. 
When i set the hard disk at top boot priority, it tries to boot it but says "
Reboot and select a proper boot device ... or boot media in selected boot device and press a key..." I'll google it.
Edit5: Google results just say about the boot priority list, but i've tried just setting the hard disk as top then disable the others or enable them all or even reset to default...
Tried using gparted to "check and repair" and "flag as boot" as suggested
here, no luck.
/ 
