Battery

If its weak replace it and see what happens don't work have he electrical system checked

Is this the old body styl S40 or the new style? The windows will be affected by the weak battery because you have lost initialization on the new body style S40. As for the A/C issue I would suspect a worn compressor clutch. Measure the gap. Spec is 0.3mm to 0.5mm if it is greater then that replacing the clutch will fix the problem. If it is within specs then the weak battery could also be causing this issue but again this applies to the new body style S40. Let us know if this helps. Once the battery is replaced you will need to have the windows reinitialized for the auto function to work properly. You may also have an EPS light on or something related to a power steering issue since the power steering pump is a control module. You could even have an SRS light on as well. So again once the battery is replaced, all fault codes need to be reset and windows initialized.

Ok then have the A/C compressor clutch clearance check. Very common problem for them to wear out. You can replace just the clutch only. You could even just have a shim removed to bring the clearance closer. As long as you can get it between 0.3mm and 0.5mm you should be good. Your best bet would be to go to a shop that specializes in A/C repairs. The dealership will most likely want to replace the clutch? For the window try this steps on your own and let me know if it works?

ALLDATA Editor's Note: Although this procedure applies to the V70, other models should be similar.

IF INITIALIZATION IS LOST THE AUTO-UP & AUTO-DOWN WILL NOT OPERATE

To initialize the driver's window:

Fully lower the window.
Close the window holding the button in the auto-up position. Continue to hold the switch in the auto up position for 5 seconds after the window is fully closed.

Or try this step if the first one does not work?

IF THE WINDOW IS NOT RESPONDING CORRECTLY TO THE SWITCH

To reset the DRIVER'S WINDOW:

Ignition key in position II
Lower the window 1-2 inches: Rock the window switch quickly from the up to the down position to lower the window 1-2 inches (this action may need to be repeated several times in a row).
Locate fuse 27 in the fuse panel at the left side of the dashboard.
Directly after activating auto-up, QUICKLY remove fuse 27.
Install fuse 27.
Press the driver's window auto-down switch and release(the window will lower some).
Repeat steps 4-6 until the window is fully down.
Perform steps A & B in "To initialize the driver's window" above.

Good luck and hope this helps you ot. Let us know what happens. Hope you got the same rated battery as well. Should be minimum 600CCA I believe?