Buying a home with 2 prong outlets but the bathroom has 3 prong outets
Grounding is no longer red-alert essential
Since there are other ways now to provide better protection.  Particularly, GFCI protection is so good that you're allowed to fit 3-prong outlets as long as they are protected by a GFCI device (somewhere in the circuit).
So all these are acceptable:

A socket that's obviously a GFCI, with &quot;Test&quot; and &quot;Reset&quot; buttons.
A socket that has a &quot;GFCI Protected&quot; sticker that is protected by a GFCI device somewhere else (e.g. GFCI breaker or GFCI socket upstream).
A 3-prong socket stickered with &quot;GFCI Protected&quot; and &quot;No Equipment Ground&quot;.

Note that GFCI does not provide &quot;Equipment Ground&quot;, or the ability of equipments to dump lightning, ESD and surges to the earth ground (which doesn't exist).
Retrofitting ground isn't as hard as it used to be
NEC 2014 broadened the rules for &quot;retrofitting ground&quot; to outlets not currently grounded.  Today, you are allowed to simply run a proper-sized ground wire, via any route, to any of the following:

The panel (obviously)
Any junction box that has a big enough ground going back to the panel
Any junction box with hard metal conduit going back to the panel
The Grounding Electrode System (bare wires from panel to water pipe/ground rods)

And circuits can share grounds -- you can't share neutral because that is normal service current and it can overload, but ground faults are rare events, and you're allowed to presume that you won't have 2 of them on 2 different circuits at the same instant.
Also, grounding may be there anyway. Some old houses were wired with metal conduit or metal-jacketed cable.  This, combined with broad use of metal boxes, sometimes means grounding actually is present after all. You can't tell this except by opening up junction boxes, but it's a pleasant surprise.   The houses done in conduit can even have the wires replaced with little pain - the conduit lasts forever.
So you can often use a &quot;combo tactic&quot; of GFCI protection + actual grounding for the receptacles in the computer room.
Worry more about the panel
Certain types of panel are toxic -- Federal Pacific and Zinsco.  Those panels must go entirely.  Swapping panels is a big job, pencil in $2000.
One panel line, Challenger, has dangerous breakers trivially replaced with modern breakers.
Other panels such as Pushmatic or old GE, are perfectly safe (Pushmatic is &quot;the finest consumer panel ever made&quot; say some), but are obsolete meaning modern safety-enhanced circuit breakers can't be obtained.  (at least not from reliable US vendors; the Chinese will supply dangerous junk of course.)
Still others (ITE, Crouse Hinds, Westinghouse, Challenger etc.) are obsolete in name, but fully supported by modern breaker lines.
The reason this matters is that AFCI and GFCI breaker types enhance safety considerably in old wiring.  AFCI attacks the problem of arc faults, or faulty old wiring that arcs, overheats and starts fires.  GFCI provides shock protection for humans which is significantly better than the protection provided by grounding.
As such, it's possible to secure old wiring and even &quot;dangerous&quot; aluminum wiring well enough to continue it in service.
Although to tell you a secret, the problem with aluminum was never the metal.  It was bad choices about attaching it to terminals not actually made for aluminum wire, and using improper screw torques.  In 2017 they require a torque screwdriver for all connections; that and CO-ALR rated receps and switches, you barely even need the AFCI breaker at that point!