I turn on my laptop ad what i get is a fan error message after which it turns off what could be the issue and how to solve it. Hit the escape key and it booted up and the fan is running full time. is this safe?

if your have faced this issue while using your computer. Then you need to follow these steps to fix UI Failed to Load on windows

https://www.mygeekshelp.com/avast-ui-failed-to-load-after-windows-10-update

Here is the remedy for that error:
We've heard a few reports of Wifi connectivity issues recently, among them 'Authentication error'. If you receive this message, our recommended remedy is to remove all Wifi connection information from your Meep, turn off your Meep, reboot your router, then turn on your Meep and re-add the Wifi information. Follow these steps exactly in this order to resolve this error message:
1. Remove all Wifi network information from the Meep's settings
2. Reboot your router
3. Re-add the Wifi network information to the Meep's settings
4. Reboot the Meep.

Back up your most important data to an external storage device in case anything goes wrong while changing the BIOS settings. Remove any disc that is currently inserted in the IBM Thinkpad X41's disc drive.
2-Shut off the Thinkpad X41 laptop. Turn the laptop back on and wait for the "To interrupt normal startup, press the blue Access IBM button" message to appear on the screen.
3-Tap the blue Access IBM button at the top of the keyboard. Click the "Access BIOS" button when the "Rescue and Recovery" menu appears.
4-Click "Yes" and wait for the BIOS to load. Type in the current BIOS password for the IBM X41 and press Enter.5-Navigate over to the IBM's "Security" heading by tapping the right arrow key twice. Scroll down to the "Supervisor Password" listing and press "F5."6-Type the IBM's current BIOS password and hit Enter. Leave the next field blank if you want to completely remove the BIOS password, or instead type in a new password to replace the old one. Press Enter.7-Press "Escape" and then highlight "Restart" and press F5. Navigate to "Save changes and Restart" and press Enter.

I had the same problem last night! Finally i found the reset button on the back of the device. It is actually a little pin hole and I stuck my earring in there and voila' it came back on. Hope this solves your issue!

Try F2 whilst booting,if you get into these pages navigate with the "tab" and "arrow" keys. Save and exit after selecting"Enter -key") or restore to defaults--good luck!

Davey Snake!

Hit escape repeatedly while booting. When you get an error message that says hit F1 DO IT. Then you will enter bios.

Keep hitting escape while starting up. Message will say there is an error and hit F1. Hit F1 and you'll enter bios.

Please have a look through the following links, to help diagnose the problem your 'beep error code' is trying to alert you to.

I hope this information allows you to resolve this issue. If you need further assistance, please post back with a comment to this thread.
If I've managed to answer your question or solve a problem, please take just a moment to rate this post....thanks!

sounds like hard disk faliure, suggest getting a new hard disk or perhaps attempt a system reinstall. Its not the fan but the hard disk.

Geoff