The most common and most likely answer to this crossword clue is the 7 letter word MALWARE
I've seen this crossword clue in The Guardian
M
A
L
W
A
R
E
More clues leading to the result MALWARE
- Fight to stop man producing harmful app
- Macho guards fighting Trojans et al
- Fighting in island capital not good for a PC
- Macho guards fighting source of cyber invasion?
- Conflict restrained by bloke’s computer programs
- Means to sabotage quantity of formal war equipment
- Trojan horse is characteristic of dismal war effort
- Man holding conflict as something corruptive
Buddy explains!
The straight part
We know that "not good for a PC" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case not good for a pc = malware.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MALWARE mean?
MALWARE noun- Software which has been designed to operate in a malicious, undesirable manner.