Lubuntu 18.04 is giving only 640 x 480 resolution option

I have an old Pentium 4 PC with 1 Gb ram . This old folk was desperately looking for a 32 bit OS .I installed Lubuntu 18.4 which installed just fine but gives only 640 x 480 resolution option which is too low . please help

The oldest supported release of Lubuntu is Lubuntu 20.04 LTS.

I’ll provide some relevant links

As such I’ve moved this post to off-topic, as the release is unsupported by Lubuntu.

Your system in my view is now a Ubuntu 18.04 LTS (it has 5 years of support, flavors do not) with the LXDE desktop (as was used by Lubuntu 18.04 LTS).

I’d suggest using ubuntu-support-status to confirm the supported status on your actual install to evaluate the security status of your own system with your actual usage of it. See the aforementioned discourse posts for examples.

Many support sites still support 18.04; but you risk getting reminders that Lubuntu 18.04 LTS is EOL, thus using Ubuntu 18.04 LTS (with LXDE) maybe easier.

I’d expect your issue relates to how your video card (gpu) is recognized. I’d personally use sudo lshw -C video to list hardware of class video. I’d hope this would provide details you can search online for clues as to fixes (note: there are some old cards that are no longer supported by any OS due to security flaws in chips - thus everyone dropped support; they may be limited to 640x480 & if that’s why & check out how the security flaws may impact your usage of the box if that’s why).

I used pentium 4, D, M & like x86/32-bit only boxes to test releases up to 19.04 with almost no issues. Some of the older boxes I used in testing preferred the GA kernel with 18.04 (ie. one was fine up to 18.04.3 or the 5.0 HWE kernel, another two were good up to 18.04.4 or 5.3 kernel but didn’t like the 5.4 kernel - however using the GA kernel stack with them all was golden).

You weren’t specific as to what 18.04 media you used (ie. which kernel stack option you used), and official sites will warn you it’s EOL unless you navigate indirectly to find the files - so I’d check you got it from a legitimate site, and look at what you’re using. l’d likely suggest trying the GA stack in live mode to see if it’s better (assuming you’re using the HWE stack; otherwise try the HWE stack if you’re using GA).

You can use uname -r to view kernel details; if you’re using the GA kernel it’ll remain 4.15 for all point releases; where as HWE moved to 4.18 with 18.04.2, 5.0 with 18.04.3, 5.3 with 18.04.4, 5.4 with 18.04.5 & higher. The kernel won’t matter though if you’re using one of the insecure or abandoned video cards.

For specific details on HWE/GA kernel stack choices of Ubuntu LTS releases you can look at