Deleting a partition ... the safest way to do it

4GB!!!??? The "safest" way to handle your problem is install MUCH bigger hard drive(s).

If in fact your primary hard drive is 4GB, anything you do to that machine is sorta like putting fresh paint on a dead horse. Your best bet, if you want to do something of practical benefit, would be to replace the drive. If its a factor (and if that hard drive really is only 4GB, its gonna be a factor)be advised that without some fiddling, Win9x operating systems (WinME and earlier) will not recognize drives larger than 32GB. There are workarounds, but motherboard and BIOS considerations may hardwall deadend any workaround.

However, if you wish to repartition your existing drive, the best and surest way to do it would be to back up to removable media everything you want to keep, then, either from from DOS or with a commercial partioning utility, delete both partitions and format the drive as a single partition, then finally reinstall your operating system, drivers, applications, and personal files/folders.

cant i do it through the bios? or through the partition utility (ex: partition magic) WITHOUT backing up?

You can do anything you want to without backing up.

Live dangerously. Go ahead. We dare you..

You don't need to back up anything that you don't mind losing.

You should back up anyway as things happen. But doing anything with your partitions drastically increases the chance of something bad happening to your data.

You should back up before doing this if you care about the data on the disk. If you don't care about the data on the disk, the easiest way to repartion a disk is to reformat it.

Wow. 4 Gb hard drive.
I have a USB stick with double that capacity.

Upgrade your drive dude.
40 gigs will be massive compared to what you have and considering you've never felt the need to change it before now you're not going to be eating up loads of space.
And you can pick them up for peanuts.
I mean really small numbers of dollars.