Effect of high frequency welding near by the electronic things

Check these two things immediately.

A line filter on the computer supply. The can be in the form of a plug that fits in the socket then you put your computer plug into the socket outlet on the filter. Ensure that your computer is on a different circuit (The circuit breaker or fuse for the computer is different to the one for the welder).

The earth of the welder. The earthing point should be as close to the point of welding as possible so as to not allow any possibility of current flowing through any adjacent cables.

If these basics don't work then you will have to think about shielding and or separate supplies.