I am running on fedora 13 (dont ask me why!)and when ever I am switching on my computer it tells me there is only 1gb left on the computer. but when I check /dev/sda5 has about 150gb free space. How do I claim this space?

If you open a terminal window and enter
what does that show you?

Could you provide the output of the following commands?
df -h
fdisk -l

as /dev/sda5 is a partition and we have no idea about the filesystem(s) created or not created on it

df -h output
Filesystem Size Used Avail Use% Mounted on
/dev/sda5 151G 8.5G 135G 6% /
tmpfs 990M 520K 989M 1% /dev/shm
/dev/sda1 194M 23M 162M 13% /boot
/dev/sda2 77G 72G 1.9G 98% /home

fdisk -l output
Disk /dev/sda: 250.0 GB, 250000000000 bytes
255 heads, 63 sectors/track, 30394 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000080

Device Boot Start End Blocks Id System
/dev/sda1 * 1 26 204800 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 26 10225 81920000 83 Linux
/dev/sda3 10225 10388 1310720 82 Linux swap / Solaris
/dev/sda4 10388 30395 160703488 5 Extended
/dev/sda5 10388 30395 160702464 83 Linux

Can you post the exact error message for "it tells me there is only 1gb left "?

/home is 77Gig, 72Gig used, you either have a lot of data, Downloads or refuse to empty trash.

edit

After examining your / has a lot of space, but your /home is getting full, either get rid of unnecessary files or resize using live-cd

The message is "The volume 'home' has only 1.8gb disk space remaining. You can free some space by removing removing programs or files or by moving files to another disk or partion"

@ Eddy Yes my home is the one which is full but my hard disk is around 250gb. In this case I am only using 78gb of that. I want to use the whole lot

If everything on /home is important use gparted-live & shrink sda2 from the right, move sda3 to the left, grow extended sda4 to the left, then grow sda5 to left filling sda4

You can find out what's taking mob space using du -sh /dev/sda5

Ireally don't think you have a use for 151 Gig /

output du -sh /dev/sda5

0 /dev/sda5

http://gparted.sourceforge.net/
http://gparted.sourceforge.net/livecd.php/

Sorry du -sh /dev/sda5/*